Voltage rating of a parallel plate capacitor is `500V`. Its dielectric can withstand a maximum electric field of `10^(6) V//m`. The plate area is `10^(-4)m^(2)`. What is the dielectric constant if the capacitance is `15pF`?
(given `epsilon_(0)=8.86xx10^(-12)C^(2)//Nm^(2)`)

Options

A. 6.2
B. 4.5
C. 8.5
D. 3.8

Answer

C

Explanation

`E_(mnax)d=V_(max),d=(500)/(106)=5xx10^(-4)m,c=(kin_(0)A)/(d) implies k=(Cd)/(in_(0)A)=(15xx10^(-12)xx5xx10^(-4))/(8.86xx10^(-12)xx10^(-4))~~8.5`.